Human-mouse hybrid cells; chromosomal assignments for human genes; multiple copies of human chromosomes in hybrid cells; excessive purine production in mammalian cells; an adenosine kinase selective system; mutagenesis; ribosomal RNA synthesis in hybrid cells; action of BCNU, fluoroadenosine, 3' deoxyadenosine on transcription and translation; defective interfering particles of poliovirus, genetic mapping of poliovirus; cleavage of poliovirus proteins; the RNA, transcriptase, and replicase of VSV; cellular RNA dependent RNA synthesis; synthesis of tumor virus RNA; reverse transcription of mRNA's; sites of DNA replication in the nucleus; direction of replication in mammalian chromosomes; characterization of carbohydrate of cell membrane glycoproteins by gas liquid chromatography; specific labeling techniques for cell membrane proteins and glycoproteins; DNA replication in isolated techniques for cell membrane proteins and glycoproteins; DNA replication in isolated nuclei; mutants defective in DNA replication; subunits in DNA replication chromosome condensation.